Dual safety hydraulic system



sept. 28, 1965 MAMORU WATANABE DUAL SAFETY HYDRAULIC SYSTEM Filed July 27, 1964 2 Sheets-Sheet 1 INVENTOR MAMO/2U WATANABE Sept, 28, 1965 MAMORU WATANABE 3,208,223

DUAL SAFETY HYDRAULIC SYSTEM Filed July 27, 1964 2 sheets-sheet 2v u, Q INVENTOR MAMofeU WA TAN/455 3,208,223 DUAL SAFETY HYDRAULIC SYSTEM Mamoru Watanabe, 16 -ciiome, Takinogawa, Kita-ku, Tokyo, Japan Filed July 27, 1964, Ser. No. 385,332 Claims priority, application Japan, July 31, 1963, 38/ 41,076 6 Claims. (Cl. 60-54.5)

This invention relates to brake control apapratus for automobiles and other vehicles.

It is known to increase the pressure of the oil supplied by an oil cylinder when the piston thereof is operated, by utilizing the power provided by the aspiration in an internal combustion engine. It is also known to increase the delivered oil pressure by means of compressed air of an air compressor, or by using the difference of air pressure 4between a vacuum and atmosphere. These arrangements have been employed to increase the fluid p1 essure in a dual power cylinder arrangement.

It is an object of this invention to associate the two power cylinders of the above described power cylinder arrangement in a single cylinder euipped with an adjusting piston. The function of transmitting the oil pressure from a tandem master cylinder, is fulfilled by two systems, using secondary oil pressure in such a way as to increase said pressure equally in both primary and secondary utilization means such as brake cylinders. In addition, such an arrangement offers the safety of retaining brake operation even if the oil pressure is lost in one system or damage arises in the operation of the power system. This invention contemplates combining all the above functions in a single power cylinder arrangement.

An embodiment of the invention is described in conjunction with the illustration in the attached drawing wherein:

FIGURE l is a schematic representation of an embodiment of the invention;

FIGURE 2 is a sectional View of a portion of the embodiment of FIG. l; and

FIGURE 3 is a sectional view on enlarged scale of a detail of FIG. 2, showing the same in a different condition of operation.

In the drawing brake pedal 1 is operative to actuate a tandem master cylinder 2 having two oil-supply systems. 3, 3 are primary oil supply conduits. 4, 4' are secondary oil supply conduits. 5 is a primary power cylinder. 6 is a secondary power cylinder. An oil pressure cylinder 7 is interposed between primary power cylinders 5 and 6. An air line 8 is indirectly connected to the power cylinders 5 and 6. An air cleaner 9 is mounted at the entrance to air line 8. An air intake tube 10 is connected to power cylinders 5 and 6 and to an intake manifold 11 of the engine. Conduits 3 and 4 supply oil cylinders 12, 13 of fluid utilization means with oil.

The oil pressure generated by the operation of brake pedal 1 is divided between the primary and secondary systems, and is multiplied in the oil pressure cylinder 7 by power cylinders 5, 6 and thereafter transmitted by oil supply conduits 3', 4 to brake cylinders 12, 13.

FIG. 2 shows the oil pressure cylinder in the position prior to the operation of tandem master cylinder 2. The spaces 16, 17, 18, 19 within cylinders 5, 6, in the front and back of each piston in both cylinders 5, 6 are placed under a vacuum as a result of the intake at manifold 11 through intake pipe 10 and check valves 2t), 21, and the pistons 14, remain in the illustrated rest position, due to the action `of return springs 22, 23 in View of the fact that the forces on pistons 14, 15 are balanced.

Thus, in the cylinder 7, the two pistons 24, 25 are at rest. Connecting rods 30, 31 connected with the pistons 24, 25 have oil outlet holes 26, 27 and Valves 28, 29 re- 3,238,223 Patented Sept. 28, 1965 spectively, as Well as Stoppers or plugs 32, 33 connected with said connecting rods. The rods are also at rest While an oil pressure adjustment piston 34 is in a central position in cylinder '7 under the action of springs 35, 36.

The length of the connecting rods 30, 31 has been so determined that ample space is available for the stroke of pistons 24, 25 towards Stoppers or plugs 32, 33 in order to provide for the fiow of the necessary amount of oil between brake cylinders 12, 13 and supply conduits 3', 4'. Furthermore, since the length of suspension springs 35, 36 between pistons 24, 25 and the plugs or Stoppers 32, 33 connected to the oil pressure pistons is limited by the length of connecting rods 30, 31, the central adjustment piston 34 when displaced towards either the primary cylinder 5 or the secondary cylinder 6, is returned to its original position, and both pistons 24, 25 can maintain the previously determined strokes to supply the appropriate amount of oil to the oil cylinders 12, 13 through conduits 3', 4'. When the brake pedal 1 is depressed to start the operation of the brake control system of this invention, oil pressure is transmitted and distributed to all brake control apparatus, and at the same time, pressure acts on the relay cylinders 36, 37 connected to the oil supply conduits 3, 4 and air pressure comes into the spaces 16, 19, of cylinders 5, 6 via air line 8 whereby, due to the vacuum existing in the spaces yon the other side of pistons 14, 15 the pistons move towards the cylinder 7, overcoming the power of return springs 22, 23 and this in turn is transmitted to each piston 24, 25 through both push rods 37, 38 which are connected to the pistons 14, 15. At that time, a secondary oil pressure will develop and be increased between piston cups 41, 42 and 43, 44 which are respectively supported in sealing relation in the cylinder 7.

As shown in FIG. 3 piston 25 is moved forward by push rod 38 of power piston 15 into contact with valve 29 to cause the head 46 of connecting rod 31 to move Within stopper 33. Valve 29 comes in contact with piston 25 by the resistance offered by valve spring 40 whereby oil hole 27 is closed, and the oil under pressure between piston cups 43 and 44 will be discharged through oil supply conduit 4'.

At that point, the motion of both pistons 24,. 25 toward the central adjustment piston 34 will cover the same stroke as the movement of plugs or stops 32, 33 toward the piston 34 and, therefore, some space will become available between pistons 24, 25 and plugs 32, 33 and between these plugs 32, 33 and the heads 45, 46 of connecting rods 30, 31. In accordance with the space available, the abovedescribed adjustment piston 34 will be able to move front and back and make the necessary oil pressure adjustments, since it moves automatically toward the chamber of lower oil pressure.

The above operation can be made by coordinating the operation of both pistons 24, 25 or by the use of one piston, while the other piston is fixed at a rest position. Thus, even if one of the power cylinders 5, 6 becomes inoperative, there will still be developed secondary oil pressure in cylinder 7. Furthermore, the following eX- planation is applicable to either the primary or secondary system. For instance, in the event the oil pressure is lost in the primary oil supply system, and the piston 14 in the primary system does not operate, the piston 15 in the secondary system can effect brake control through the secondary brake cylinder 13 which will then operate, through the oil supply conduit 4', by the multiplying of secondary oil pressure occurring between the piston 34, and the piston 25, after the strokes have been made ineffective when stopper 32 reaches piston 24.

As fully described above, this invention can achieve effective brake control by means of the secondary oil pressure which has been multiplied on either side, even if one of the sections or the oil pressure supply apparatus becomes inoperative due to a defect or damage. Moreover, this invention can also achieve a smooth supply of equal oil pressure very effectively through two power systems, when both systems are working effectively.

What is claimed is:

ll. Brake control apparatus comprising a master cylinder having a primary and secondary iluid supply system, a conduit for each system connected to the master cylinder, and means operatively associated with said master cylinder for supplying iluid under pressure to each said conduit, the apparatus further comprising rst and second pressure fluid utilization means including a respective conduit for the supply of pressure fluid and intermediate uid control means connecting the conduits from the master cylinder with the conduits of the utilization means, said intermediate fluid control means including means for multiplying the pressure of the tluid received from the conduits of the master cylinder for delivery to the conduits of the fluid utilization means, and means controlling respective delivery of iluid between the conduits of the master cylinder and the fluid utilization means to provide delivery of pressure iiuid to one of the utilization means with the other of the utilization means and the iluid supply system associated therewith inoperative, said means which controls delivery of tluid comprising a cylinder, a central piston slidably supported in the latter cylinder and defining iirst and second separate chambers therein, irst and second piston means respectively supported in the chambers of the latter cylinder for slidable movement, said conduits which are connected to the master cylinder being connected to and opening into the cylinder of the iluid Control means on a respective side of said central piston therein for supplying pressure fluid thereto, said means for multiplying the luid pressure comprising power means coupled to respective of the irst and second piston means for displacing the same within the cylinder of the fluid control means to increase the pressure of the fluid supplied to the chambers for delivering fluid under still greater pressure to the fluid utilization means.

2. Apparatus as claimed in claim l wherein the rst and second piston means respectively comprise a piston body slidable in the cylinder of the intermediate uid control means, a connecting rod slidable in said body, a plug constituted of a hollow body in which said connecting rod is slidable, a spring in said hollow body resisting movement of said connecting rod therein, said connecting rod having an opening establishing communication between the conduit from the master cylinder and the conduits of the fluid utilization means, a valve on the connecting rod closing said opening and thereby said communication as the piston body is displaced into contact with the valve under the action of the power means whereby a quantity of pressure duid is entrapped in the cylinder of the fluid control means such that further displacement of the piston by the power means causes increase of the pressure of the lluid supplied to the fluid utilization means.

3. Apparatus as claimed in claim l wherein said power means for each said piston means comprises a cylinder and a piston in said cylinder, means for establishing a difference of pressure in the latter cylinder on opposite sides of the piston therein to displace the latter piston, means connecting the latter piston to the said piston body of the associated of said piston means for common displacement, and means controlling7 the establishment of said pressure difference in the cylinder of the power means in accordance with the supply of pressure fluid to the conduit of the master cylinder connected to the particular chamber of the tluid control means of the associated piston means.

4. Apparatus as claimed in claim l wherein said means which controls delivery of 'luid further comprises a piston cup located immediately on either side of the central piston in sealing relation in the cylinder, and a piston cup supported on each piston body in sealing relation with the cylinder.

5. Apparatus as claimed in claim d wherein the conduits from the master cylinder open into the cylinder of the fluid control means on a side of the piston cups on the piston bodies opposite the central piston, said conduits of the fluid utilization means opening into the cylinder of the fluid control means in spaced location from the conduits of the master cylinder and closer to the center piston.

6. Apparatus as claimed in claim 5 comprising a spring between the piston body and the associated plug of the respective piston means.

References Cited by the Examiner UNETED STATES PATENTS 2,887,187 5/59 Fletcher et al @-54.6 X 2,911,263 ll/59 Hill 303-6 SAMUEL LEVINE, Primary Examiner.

ROBERT R. BUNEVICH, Examiner. 

1. BRAKE CONTROL APPARATUS COMPRISING A MASTER CYLINDER HAVING A PLURALITY AND SECONDARY FLUID SUPPLY SYSTEM, A CONDUIT FOR EACH SYSTEM CONNECTED TO THE MASTER CYLINDER, AND MEANS OPERATIVEY ASSOCIATED WITH SAID MASTER CYLINDER FOR SUPPLYING FLUID UNDER PRESSURE TO EACH SAID CONDUIT, THE APPARATUS FURTHER COMPRISING FIRST AND SECOND PRESSURE FLUID UTILIZATION MEANS INCLUDING A RESPECTIVE CONDUIT FOR THE SUPPLY OF PRESSURE FLUID AND INTERMEDIATE FLUID CONTROL MEANS CONNECTING THE CONDUITS FROM THE MASTER CYLINDER WITH THE CONDUITS OF THE UTILIZATION MEANS, SAID INTERMEDIATE FLUID CONTROL MEANS INCLUDING MEANS FOR MULTIPLYING THE PRESSURE OF THE FLUID RECEIVED FROM THE CONDUITS OF THE MASTER CYLINDER FOR DELIVERY TO THE CONDUITS OF THE FLUID UTILIZATION MEANS, AND MEANS CONTROLLING RESPECTIVE DELIVERY OF FLUID BETWEEN THE CONDUITS OF THE MASTER CYLINDER AND THE FLUID UTILIZATION MEANS TO PROVIDE DELIVERY OF PRESSURE FLUID TO ONE OF THE UTILIZATION MEANS WITH THE OTHER OF THE UTILIZATION MEANS AND THE FLUID SUPPLY SYSTEM ASSOCIATED THEREWITH INOPERATIVE, SAID MEANS WHICH CONTROLS DELIVERY OF FLUID COMPRISING A CYLINDER, A CENTRAL PISTON SLIDABLY SUPPORTED IN THE LATTER CYLINDER AND DEFINING FIRST AND SECOND SEPARATE CHAMBERS THEREIN, FIRST AND SECOND PISTON MEANS RESPECTIELY SUPPORTED IN THE CHAMBERS OF THE LATTER CYLINDER FOR SLIDABLY MOVEMENT, SAID CONDUITS WHICH ARE CONNECTED TO THE MASTER CYLINDER BEING CONNECTED TO AND OPENING INTO THE CYLINDER OF THE FLUID CONTROL MEANS ON A RESPECTIVE SIDE OF SAID CENTRAL PISTON THEREIN FOR SUPPLYING PRESSURE FLUID THERETO, SAID MEANS FOR MULTIPLYING THE FLUID PRESSURE COMPRISING POWER MEANS COUPLED TO RESPECTIVE OF THE FIRST AND SECOND PISTON MEANS FOR DISPLACING THE SAME WITHIN THE CYLINDER OF THE FLUID CONTROL MEANS TO INCREASE THE PRESSURE OF THE FLUID SUPPLIED TO THE CHAMBERS FOR DELIVERING FLUID UNDER STILL GREATER PRESSURE TO THE FLUID UTILIZATION MEANS. 